Etching method and plasma processing apparatus

Abstract

Provided is a technique for improving a mask selectivity in etching. An etching method according to the present disclosure includes step (a) preparing a substrate including a silicon-containing film and a mask on the silicon-containing film, the mask including an opening pattern, step (b) forming a metal-containing film on the mask, and step (c) etching the silicon-containing film by generating the plasma from a first processing gas containing a hydrogen fluoride gas.

1 . An etching method comprising:
 step (a) providing a substrate including a silicon-containing film and a mask on the silicon-containing film, the mask including an opening pattern;   step (b) forming a metal-containing film on the mask; and   step (c) etching the silicon-containing film by generating plasma from a first processing gas containing a hydrogen fluoride gas.   
     
     
         2 . The etching method according to  claim 1 , wherein the silicon-containing film includes a silicon oxide film, a silicon nitride film, a polysilicon film, or a laminated film including two or more types of the silicon oxide film, the silicon nitride film and the polysilicon film. 
     
     
         3 . The etching method according to  claim 1 , wherein the mask includes a silicon-containing film different from the silicon-containing film, a carbon-containing film or a metal-containing film. 
     
     
         4 . The etching method according to  claim 1 , wherein the mask includes an amorphous carbon film or a spin-on carbon film. 
     
     
         5 . The etching method according to  claim 1 , wherein the mask includes a film including at least one type of metal selected from the group including tungsten, molybdenum, titanium, and ruthenium, or
 wherein the mask includes an oxide film, a nitride film, or a carbon film including the at least one type of metal.   
     
     
         6 . The etching method according to  claim 1 , wherein step (b) includes forming the metal-containing film from a second processing gas containing a metal-containing gas. 
     
     
         7 . The etching method according to  claim 6 , wherein the metal-containing gas includes at least one type of metal selected from the group including tungsten, molybdenum, titanium, and ruthenium. 
     
     
         8 . The etching method according to  claim 7 , wherein the metal-containing gas includes tungsten hexafluoride or molybdenum hexafluoride. 
     
     
         9 . The etching method according to  claim 6 , wherein step (b) includes forming the metal-containing film by generating plasma from the second processing gas. 
     
     
         10 . The etching method according to  claim 1 , wherein step (b) includes forming the metal-containing film by causing the mask to adsorb a metal-containing precursor. 
     
     
         11 . The etching method according to  claim 10 , wherein step (b) includes forming the metal-containing film by generating plasma from a second processing gas that oxidizes or reduces at least a portion of the metal-containing precursor adsorbed by the mask. 
     
     
         12 . The etching method according to  claim 11 , wherein in step (b), a portion of the metal-containing precursor adsorbed by the mask is not oxidized or reduced. 
     
     
         13 . The etching method according to  claim 1 , wherein step (b) includes forming the metal-containing film by physical vapor deposition (PVD). 
     
     
         14 . The etching method according to  claim 13 , wherein step (a) includes disposing the substrate on a substrate support, and
 step (b) includes forming the metal-containing film by sputtering a metal-containing electrode disposed to face the substrate support.   
     
     
         15 . The etching method according to  claim 1 , wherein the first processing gas further includes a phosphorus-containing gas. 
     
     
         16 . The etching method according to  claim 15 , wherein the phosphorus-containing gas includes phosphorus halide or phosphorus chloride. 
     
     
         17 . The etching method according to  claim 1 , wherein the first processing gas includes a carbon-containing gas. 
     
     
         18 . The etching method according to  claim 1 , wherein the first processing gas further includes a halogen-containing gas. 
     
     
         19 . The etching method according to  claim 1 , wherein the first processing gas includes at least one type of gas selected from the group including an oxygen-containing gas, a boron-containing gas, and a metal-containing gas. 
     
     
         20 . The etching method according to  claim 1 , wherein the first processing gas includes hydrogen fluoride, and
 wherein a flow rate of the hydrogen fluoride gas is highest among gasses present in the first processing gas.   
     
     
         21 . The etching method according to  claim 1 , wherein in step (b), a temperature of the substrate support that supports the substrate is set to a first temperature, and
 in step (c), the temperature of the substrate support is set to a second temperature that is lower than the first temperature.   
     
     
         22 . The etching method according to  claim 21 , wherein the first temperature is 0° C. or higher, and the second temperature is lower than 0° C. 
     
     
         23 . The etching method according to  claim 1 , wherein a cycle including step (b) and step (c) is repeated multiple times. 
     
     
         24 . An etching method comprising:
 step (a) preparing a substrate including a silicon-containing film and a mask on the silicon-containing film, the mask including an opening pattern;   step (b) forming a metal-containing film on the mask; and   step (c) etching the silicon-containing film by generating plasma from a first processing gas.   
     
     
         25 . The etching method according to  claim 24 , wherein the first processing gas includes one or more gases that generate a hydrogen fluoride species. 
     
     
         26 . A plasma processing apparatus comprising:
 a power source;   a chamber including an electrostatic chuck;   a temperature controller;   a gas introducer including a shower head; and   circuitry configured to:
 control at least the temperature controller to prepare a substrate including a silicon-containing film and a mask on the silicon-containing film in the chamber, the mask including an opening pattern, 
 control at least the gas introducer to form a metal-containing film on the mask, and 
 control at least the power source, the gas introducer and the electrostatic chuck to etch the silicon-containing film by generating plasma from a first processing gas containing a hydrogen fluoride gas.